Definition and Properties of Normal Salt
Definition: a salt that contains neither hydrogen ions capable of ionization nor hydroxide ions.
The ortho salt is the product of complete neutralization of an acid and a base, but an aqueous solution of an ortho salt is not necessarily neutral, e.g., Na2CO3 (sodium carbonate) solution is alkaline and (NH4)2SO4 (ammonium sulfate) solution is acidic. The salt produced by complete neutralization of an acid with a base will not have hydrogen ions from the acid or hydroxide ions from the base, but only metal cations and acid ions; such a salt is a normal salt.
Reactions that produce positive salts, e.g., HCl + NaOH = NaCl + H2O H2SO4 + Cu(OH)2 = CuSO4 + 2H2O H2SO4 + 2NaOH = Na2SO4 + 2H2O, etc.
Acid salts
Definition: cations that are produced during ionization that have a hydrogen ion in addition to the metal ion (or NH4+). The anions are salts of acid ions.
According to the composition of acid salts and the changes that may occur when dissolved in water, there are the following cases:
(1) Acid salts of multiple strong acids This type of salt dissolved in water, can be completely ionized, so that the solution shows a strong acidity, such as NaHSO4 (sodium bisulphate) NaHSO4 = Na+ ＋ H + ＋ SO4 2- (2) Acid salts of multiple weak acids This type of salt dissolved in water, the acid acid ions at the same time undergo hydrolysis. Acid acid ions at the same time hydrolysis and ionization, due to hydrolysis and ionization of the degree of difference, resulting in a solution showing different acidity and alkalinity. For example, NaH2PO4 (sodium dihydrogen phosphate) solution is weakly acidic and Na2HPO4 (disodium hydrogen phosphate) solution is weakly basic. Usually only the acid salts of weak acids containing the H2PO4 and HSO3 roots are acidic. NaH2PO4 = Na+ + H2PO4- H2PO4- ?HPO4 2- + H+ H2PO4- + H20 ?H3PO4 + OH- H2PO4- ionization of c (H+) is greater than it hydrolyzes to generate c (OH-), so the solution is weakly acidic; and Na2HPO4 solution, HPO4 ionization of c (H+) is less than it hydrolyzes to generate c (OH-), so the solution is weakly basic. When an acid reacts with a base, the hydrogen ions in the weak acid are partially neutralized, and there are hydrogen ions in the resulting salt in addition to metal cations and acid ions, so the salt is an acid salt. For example, NaHSO4, KHCO3, KH2PO4, K2HPO4, Ca(HCO3)2, etc. are acid salts. Unitary acids cannot form acid salts, while dibasic or polyacids can form acid salts. There are many types of acid salts with different properties. Some of the aqueous solutions of acid salts are acidic, such as NaHSO4, KHSO4, KH2PO4, etc.; HSO4 acid salts in aqueous solution can be ionized out of H+ and SO4 2- Some are alkaline, such as KHCO3, K2HPO4, etc. Hydrolyzed. Na2SO3 is basic .
Basic salts
Definition: salts in which the anions produced on ionization are hydroxide ions in addition to acid ions, and the cations are metal ions (or NH4+).
When an acid reacts with a base, the hydroxide ions in the weak base are partially neutralized and the resulting salt is a basic salt. A monobasic base cannot form an alkali salt, but a dibasic or polybasic base may form an alkali salt. The composition and properties of alkali salts are complex and varied. Alkali copper carbonate Cu2(OH)2CO3 and alkali magnesium chloride Mg(OH)Cl are alkali salts. Alkali salts contain 1 or n hydroxyl or oxygen groups in addition to metal and acid radical ions. Alkali salts can also be thought of as the product of a base in which the hydroxide root is not completely neutralized by the acid. Hydroxyl salts can be viewed as complex salts of metal ions with OH- and other anions, e.g. Mg(OH)Cl can be viewed as a complex salt of Mg2+ with OH- and Cl-. Oxygenated salts, also known as oxidized salts, can be viewed as complex salts composed of metal ions with O2- and other anions, e.g., SbOCl can be viewed as a complex salt composed of Sb3+ with O2- and Cl-. Many alkali salts are not very soluble. The composition of some alkali salts varies depending on the conditions of preparation. For example, a mixture of copper sulfate solution and calcium carbonate heated to 423-443 K in a closed tube yields Cu(OH)2-CuCO3, while Cu(OH)2-2CuCO3 is produced at lower temperatures.
Complex salts
Definition:Homocrystalline compounds consisting of two or more simple salts are called complex salts (a salt consisting of two or more cations and an anion). one anion). Complex salts are also called heavy salts. Complex salts contain a number of ions of similar size that fit into the same crystal lattice.
For example, alum (potassium aluminum sulfate) is KAl(SO4)2-12H2O, molybdenum (ammonium ferrous sulfate) is (NH4)2Fe(SO4)2-6H2O, and ferric potash alum (potassium iron sulfate) is KFe(SO4)2-12H2O. when a compound salt is dissolved in water, it ionizes the same ions as do the simpler salts that make it up. Complex salts can be made by crystallizing a mixed saturated solution of two simple salts. For example, a mixed solution of CuSO4 and (NH4)2SO4 can be crystallized to produce ammonium copper sulfate [(NH4)2SO4-CUSO4-6H2O].